Well I'm just about finished with my winter restoration of a 92 Max IV. I bought new rims and tires from R.C. I didnt have the $ for the larger tires so I went with the 21 inch tires. Just looking for some opinions / experience on running the smaller tires. If nothing else I'll keep them for my future track project.

Mike, In my opinion, on a Max IV, the 21" tires should be used only for tracks (That is true for a Max II also In my opinion).

It is PSI on the ground that allows a max (any skid steer 6x6 or 8x8) to have the flotation to get through the soft stuff. The bigger the tire footprint and the deeper the tread, the better in the mud and snow. The Max IV with its extra weight needs the 26" tire to be its best (The 25" Rawhide III is essentially the same size as the 26" terra grip).

If you already bought the tires, you might as well use them. The 26's are much better, but you will still be amazed where you can go with the 21's. Keep an eye out for rocks and things, because there is not much ground clearance with the smaller tires. One of John Schwabs videos from Copper Ridge shows an older red Max IV with 21's going through some pretty rough stuff.

I'm not sure what to do. I probably jumped the gun and bought these in my excitment to finsh my project. I've totaly restored this from the frame up and my wife patience is wearing thin if you know what I mean. Another consideration is that I only have a 16 hp briggs which might be under powered for 26 inch tires. The machine had 22 inch rawhide III that were on their last leg. I went with the 21 inch thinking that the wouldnt be that much smaller and wanted to buy from Richard Clark because He's been great to deal with during this project (he doesn't carry 22 inch). What can I expect for water speed with these? If these won't move the machine in the water then I'll consider changing them

mike the 21"s can go faster than the 22"s in the water, also if you want to air them down for smother ride they are more efective than the stiffer 22"tires. 22"s have better ground clearence than the 21" ones of coarse, you cant beat the water speed of the 26" tires

The 21" Rawhide tires have a better tread pattern for paddling water. The 22" tires are much more aggressive for mud, but every third lug is short. There is about a 1-2mph difference between these two tires. A 16hp engine is a small one for 26" tires. A Max IV with at least the 20hp Kohler turning 26" tires is a beast of a machine. 6mph+ water speed, 10" ground clearance, and enough tread on the ground to take about any mud hole. Put the 26" tires on k-rims! They're a disaster in ruts without good bead locks.